12.1 Refraction Mr. Dvorsky SNC2D1

Review of last chapter From the last chapter, we know how light behaves when it travels in space or in the air – i.e. it travels in a straight line. When light strikes a plane mirror, the angle of incidence = the angle of reflection.

Refraction We will now look at what happens to light when it travels from one material to another.

Some terms

The rules of refraction 1.The incident ray, the refracted ray, and the normal all lie in the same plane. The incident ray and refracted ray are on opposite sides of the line that divides the two media. 2.Light bends towards the normal when the speed of light in the second medium is less than in the first medium. The light bends away from the normal when the speed is greater in the second medium.

The bent spoon Light coming from the spoon enters the air from the water and refracts away from the normal. The -human brain perceives light to travel in a straight line and projects the refracted ray back

12.1 Refraction Problem: One medium is vinegar, which has a speed of light of 2.30 x 10 8 m/s. The other medium is sapphire in which light has a speed of 1.69 x 10 8 m/s. Use this information to identify medium 1 and medium 2.

Partial reflection and refraction Refraction is often accompanied by reflection. Some of the light that hits the water is refracted but also some is reflected. This is called partial reflection and refraction. If glass has a special coating to allow some incident light in, can make sunglasses and two way mirrors.